162 



THE BIOLOGY OF MARINE ANIMALS 



external respiration ; existence of respiratory pigments and their physico- 

 chemical characteristics. 



Metabolism Directly Dependent on 2 Tension. In many animals 2 

 consumption varies directly with 2 tension, e.g. Actinia, Nereis, Calamus, 

 Homarus, Callinectes, Limulus, Asterias. In Actinia equina, for example, 



i.ooo-i 



c: 

 o 



S*7<KH 



? y 



K 



10 



Tom Cod 



4 



1* 

 t 



r 



$- 



1000 



100 



i\ 



10 



Sculpin 



Jk 



10 20 30 40 10 20 



T e m p e rat u re (°C) 



30 40 



1000^ 





100- 



10 



Serjeant Major 



1000 ^ 



I 



i 



+ 



100- 



# 



3 



w 



Snapper 



4 



I 



f 







10 



20 



30 



40 



30 40 10 20 



Temperature (°C) 



Fig. 4.12. Respiration in Tropical and Arctic Fish 



Ordinates in c.c. 2 /kg/hour. Abscissae, temperature (°C). Tropical fish: sergeant 

 major Abudefduf saxatilus; snapper Lutianus apodus. Arctic fish: torn (polar) cod 

 Boreogadus saida; sculpin Myoxocephalus quadricornis hexacornis. (From Scholander 

 et al. (142).) 



oxygen consumption increases threefold when the external tension is 

 raised from 55-220 mm Hg. When the 2 concentration falls below 2 

 c.c./l. Actinia moves to the surface, and if this is prevented the animal 

 secretes some mucus, closes up and enters upon a period of latent life. In 

 large coelenterates diffusion is a limiting factor in the supply of 2 to the 

 tissues. In very small animals, larvae and eggs, 2 uptake remains steady 



